| Director: |
Sally Letsinger |
| Other Researchers: |
Cristian Medina,
Greg Olyphant, Byron Stone (USGS), Kevin Spindler, David Lampe, Tae Hong Kim
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| Funding: |
U.S. Geological Survey (USGS) - Great Lakes Geologic Mapping Coalition
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| Issue: |
Three-dimensional representations of complex unconsolidated subsurface geology are often constructed for input into ground-water flow models. The complexity of the geological relationships is difficult to realistically represent; therefore, the models are often oversimplifications of actual conditions. However, it is not known whether three-dimensional representations generated by mapping experts or statistical data interpolations of complex geological conditions are preferable for the purpose of simulating ground-water flow through such materials. |
| Objective: |
The objective of this project is to scientifically assess the performance of three-dimensional hydrogeologic models developed by pure statistical data interpolation and three-dimensional hydrogeologic models developed by experienced geologists familiar with the emplacement mechanisms of geologic materials. |
| Approach: |
A hydrogeologic model will be developed for Berrien County, Michigan, using three-dimensional kriging algorithms from standardized lithologic descriptions in water-well logs. A separate hydrogeologic model will be developed by a U.S. Geological Survey geologist for the same area. After the 3-D models are constructed, hydraulic conductivity grids will be generated so that identical ground-water flow simulations can be conducted on the different geologic representations. The results will be compared statistically to complete the assessment. |
| Products: |
Two three-dimensional depictions of the subsurface geology of Berrien County, Michigan, will be developed. Ground-water flow simulations for each model will be produced. Statistical analyses and summaries will be available. |
| Benefits: |
This project has great potential to emphasize the advantages or disadvantages of different methods of developing hydrogeologic models to use in ground-water flow simulations. It is unknown if statistically accurate, but geologically blind, models can accurately represent ground-water flow. Conversely, bounding surfaces between geologic units might have controls on ground-water flow that are unexpected, but important, perhaps suggesting that geologic interpretations are critical components of developing subsurface representations of heterogeneous geologic materials. |
| Publications: |
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Dressing the emperor (groundwater-flow model) of glacial geology: A tale of three tailors.
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| Olyphant, G.A., Medina, C.R., Letsinger, S.L., 2006, Dressing the emperor (groundwater-flow model) of glacial geology: A tale of three tailors. Geological Society of America Abstracts with Programs, vol. 38, no. 7, p. 108.
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GIS-based potential recharge- and discharge-area mapping from three-dimensional hydrogeologic modeling in glacial terrains of the midwestern United States
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| Letsinger, S.L., and Olyphant, G.A., 2008, GIS-based potential recharge- and discharge-area mapping from three-dimensional hydrogeologic modeling in glacial terrains of the midwestern United States. Geological Society of America Abstracts with Programs, vol. 40, no. 6, p. 472.
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The role of GIS in the development of three-dimensional hydrogeologic models
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| Letsinger, S.L., Olyphant, G.A., Medina, C.R., 2006, The role of GIS in the development of three-dimensional hydrogeologic models. Geological Society of America Abstracts with Programs, vol. 38, no. 7, p. 164.
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The Role of three-dimensional information visualization software in the development of three-dimensional hydrogeologic models
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| Medina, C.R., Olyphant, G.A., Letsinger, S.L., 2006, The Role of three-dimensional information visualization software in the development of three-dimensional hydrogeologic models. Geological Society of America Abstracts with Programs, vol. 38, no. 7, p. 164.
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